you dont you replace the whole thing
More likely the temp sensor has gone bad than the gauge is actually bad.
Evaporator temp should be 15 Degrees. Gauge pressure should be around 15psig
why doesn't my rpm gauge and temp gauge, fuel gauge not work
1996 prelude temperature gauge reads low temp
temp gauge is stuck on hot
only 3 reasons a temp gauge wont work the temp sender is bad the gauge is bad or the wire from temp sender to gauge is broken
The temp sending unit for the temp gauge is located on the drivers side of the engine between cylinders 3 and 5 spark plugs.
Thermostat stuck open or no stat at all. Faulty temp sensor or Gauge.
Replacing the gauge could be a costly job but it is seldom the gauge goes bad. More likely the temp gauge sending unit is at fault. Replacing the temp gauge sending unit would take less than 15 minutes.
If your temperature gauge isn't working the problem is a bad gauge, grounded or disconnected wiring or, most likely, the temp sender isn't working.
Test gauge function with a mechanical gauge to get actual engine temp.
i change the thermostat and the temp switch but still not working